Some advice on visiting haunts...don't just focus on the big high budget ones. Unless you have a huge budget as well, you won't be doing what they do, at least at the start. Visit big haunts, small haunts, charity haunts, for profit haunts, well run haunts, poorly run haunts, creative haunts, lackluster haunts...every single one of them will have things to teach you, both positves and negatives.
I go to a lot of haunts ranging from yard haunts to big budget productions. With every single time I visit a haunt, I always try to walk away with 3 dos and 3 don'ts. I've ended up with a pretty good list off of that. What things do I really like from the haunt, or what lessons do they teach? What places do I see where I say "I'd do that different." When starting, you have a vision of what you want to accomplish, but keep an open mind as you see what others do.